Once upon a time, in a land far, far away, Gurg learned that he could stop his neighbor, Brob, from taking his portion of mammoth by hitting him with a stick just below the eyes.  Somewhere else, some other prehistoric dude found poking Zur in the eyeball helped him impress the local prehistoric babes.  Since then, humans have found numerous ways to hit, kick, maim and otherwise kill each other.  Some have organized their techniques into whole systems.  Some of these you may know: kung fu, karate, tae kwan do, and that barbaric sport pigeon-do.  Never heard of pigeon-do? It’s by far the deadliest martial art known to man, even worse than krav maga.